feat(tinytype): support for serialising Error objects to JSON

jan-molak · Aug 3, 2022 · 50cfee6 · 50cfee6
1 parent 11fc1a7
commit 50cfee6
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Showing 2 changed files with 32 additions and 0 deletions.
diff --git a/spec/TinyType.spec.ts b/spec/TinyType.spec.ts
@@ -280,6 +280,20 @@ describe('TinyType', () => {
                     expect(parameters.toJSON()).to.deep.equal(['apples', 'bananas', 'cucumbers']);
                 });
 
+                it(`should serialise an Error as its stack trace`, () => {
+                    class CustomError extends TinyTypeOf<Error>() {
+                    }
+
+                    const error = thrown(new Error('example error'))
+
+                    const customError = new CustomError(error);
+
+                    expect(customError.toJSON()).to.deep.equal({
+                        message:    'example error',
+                        stack:      error.stack,
+                    });
+                });
+
                 it('should serialise a plain-old JavaScript object with nested complex types recursively', () => {
                     interface NotesType {
                         authCredentials: {
@@ -432,3 +446,11 @@ describe('TinyType', () => {
         });
     });
 });
+
+function thrown<T>(throwable: T): T {
+    try {
+        throw throwable;
+    } catch (error) {
+        return error as T;
+    }
+}
diff --git a/src/TinyType.ts b/src/TinyType.ts
@@ -150,6 +150,8 @@ function toJSON(value: any): JSONObject | NonNullJSONPrimitive {
             return toJSON(Array.from(value));
         case value && isRecord(value):
             return recordToJSON(value);
+        case value && value instanceof Error:
+            return errorToJSON(value);
         case isSerialisablePrimitive(value):
             return value;
         default:
@@ -170,6 +172,14 @@ function recordToJSON(value: Record<any, any>): JSONObject {
     return Object.fromEntries(serialised);
 }
 
+function errorToJSON(value: Error): JSONObject {
+    return Object.getOwnPropertyNames(value)
+        .reduce((serialised, key) => {
+            serialised[key] = toJSON(value[key])
+            return serialised;
+        }, { }) as JSONObject;
+}
+
 function isSerialisableNumber(value: unknown): value is number {
     return typeof value === 'number'
         && ! Number.isNaN(value)